Pasteurizing system



Dec. 7, 1948. RE. OLSON PAS'TEURIZING SYSTEM 2 Sheets-Sheet 1 Filed Feb. 7, 1947 INVENTOR. RAYMOND E. OLSON Dec. 7, 1948. R. E. OLSON I PASTEURIZING SYSTEM 2 Sheets-Sheet 2 Filed Feb. 7 1947 INVENTORQ RAYMOND E. OLSON Patented Dec. 7, 1948 U N I TED i S ES PATENT OFFICE PAS ZPEURIZING SYS T-EM Raymond E; lson, Pittsford, N. Y., assignor to Companies, Rochester, N. Y., a corporation of New York Application February =7, 1947,iSerial No. 727,086

. Taylor .Instrument i 1 1 This invention relates to aipasteurizing system.

flowing unpasteurizedliquid so that a portion of the heat in the ,pasteuriz edliquid can be recovered. If a leak .develops'in theregenerator of the present apparatus .it i S ipOssib1e,,under certain pressure conditions, for the unpasteurized liquid to leak into .the pasteurized liquid with the resultant contamination;

In accordance with the present inventionthere is provided a pasteuriz'ing system in" which the pasteurized liquid is normally maintained at a higher pressure than the. pressure of the unpasteurized liquid in heat exchangerelation therewith so that any leakage willbe from. the pasteurized liquid to the unpasteurized liquid and notvice versa. However, if this normalpressure condition becomes reversed, provision is made for stopping the flow of atleast one of said liquids.

The various featuresland advantages of them vention will appear from the detailed description and claims when taken with the drawing in which Fig. 1 is a diagrammatic showing of, a ,pasteuriz ing system in accordance with the pres entinvention; Fig. 2 is aflongitudinalsection through a 'dif. ferential switching .unit which is incorporated in the system of Fig. 11 and which forms aQpartlofthe present invention; and Fig. 3 is a detailed view of a portion of the switching unit, partially broken away showing the micro-switch and its mounting.

The present invention is intended for use in a pasteurizing system morecompletely disclosed in applicants copending applicati'oh' serial No. 716,- 222, filed Dec; :14, 1946. i In that system there is employed a combined pasteurizing unit 5 and a regenerating unit 6. In the pasteurizing unit the milk or; other liquid to be pasteurized flows through a'setof coils'or plates Tin heat exchange relation to a set of heating coils or plates *8 through which there is recirculated water maintained at a temperature slightly above the pasteurizing temperature.

The regenerating unit 6 includes two passageways 9 and Ill in heat exchange relation to each other. The raw milk from the tank I l is pumped by the pump l2 through the passageway 9 and by the timing pump i3 through the passageway l of the pasteurizer. The milk leaving the pasteurizer passageway '1 passes into a suitable holding tube H through which it travels for the required fifteen second holding interval required in so-called short time pasteurization and then passes through the 3 "Claims. (01. esp-2) flow diversion valve FDthrough the passageway Hliof the regenerator. Thus the regenerator conducts the pasteurized milk from the pasteurizcr in .heat exchange relation to the raw milk in the passageway 9 thereby serving'to cool the pasteurizedmilk and to heat partially, the incoming raw milk. i i

.If;hOW8V81, the milk has not been heated to the proper temperature in passageway I, suitable means, :as shown in the mentioned Olson appli: cation, operates the flow diversion valve .FD, to

divert the improperly processed Ymilk through a pipe I4 to the tank ll so that this milk can be reprocessed. The two passageways .9 and Ill through theregenerator, are normally defined by a series of plates that can be readily taken apart.

milk in the other passage, then the pasteurized.

milk will become. contaminated.

In accordance with the present invention, pro-1 vision is made for insuring .that the pasteurized milkin the regenerator will always be ata higher pressure than the raw milk in the regenerating unit so that any leakage in the regenerator will be from the pasteurized milk to the raw milk. If, however, this desiredlpressurerelation becomes reversed, there isprovided a differential pressure unit which will immediately function to stop the flow of milk throughone orboth passages in the regenerator. For thisfpurpose there is provided a sanitary differential pressure un'itP, including a T -shaped fitting t5 having its opposing ends respectively sealed by the flexible corrugated diaphragms Hiand i l, which, arebackedfby suitable protective stops lfia and Ila. A branch pipe 18 which is connected to the inlet of the passageway 9, applies the pressure of the raw milk to the lower surface of the diaphragm 11. Similarly, the

branch "pipe 19 which is connected "to the outlet of the pasteurized milk passageway I0, applies the pressure of the pasteurized milk to the upper surface of the diaphragm IS. A rod 2|] of adjust having its outer margin adapted to be sealed to the fitting in the opening 22. The plate 25 carries a projecting support 23. The support has pivoted thereon at 27, a lever 28 on the lower end of Which the microswitch 23, is supported. The lever 28 is pivotally mounted so that the button 24 of the microswitch 23 can be swung toward or away from the bracket 2i in order to select the pressure Value at which the microswitch will be operated. The swinging adjustment of the lever 28 may be efiected in any well-known manner. As herein illustrated, this adjustment is effected by a flange 30 on the outer end of the lever 28 and a cooperating flange 31 on the outer end of the support 26, both flanges being in parallel planes which are also parallel to the principal axis of the lever 28. A difierential adjusting screw 33, which passes through a coil spring 34 interposed between the flanges 3D and 3|, is threaded into both of these flanges. Thus when the screw 33 is turned in one" direction, these flanges will be drawn toward each other and when the screw is turned in the other direction the flanges will tend to be separated with the consequent swinging movement of the lever 28.

Y The plate 25 also has secured thereto the support 34 which projects therefrom in a direction parallel to the support 26. The support 34 terminates at its outer end in an angular flange 35. This flange carries the conductors 36 leading to the microswitch 23, and also tightly holds the rim of a'cuplike closure 3'1 in sealed relation with the plate 25.

When starting the system in operation the ordinary toggle switch 40 is operated to close a break 1 point in the electrical operating circuit. At the same time the pump I3 is started by means (not shown) and the non-locking manual key 4| is held depressed.- The closure of this key completes a circuit from conductor 42 leading to the current source, winding of the relay 43, switch 40, now closedand contacts of the manualkey, now depressed, conductor 44, to conductor 45 leading to the current source. Relay 43 is energized in this circuit and at its front contacts, the conductors 42,145 and 46 are closed from the power source to the motor (not shown), which drives the pump 12;. As soon as the normal flow of raw milk and pasteurizedm'ilk is established in both passages of the regenerator, the manual key 41 can be rer leased, since the circuit of relay 43 will be maintained'by the microswitch 23, through conductors 44 and 41, as long as the pressure of the pasteurized milk in the passage 10 and branch ['9 is greater than the pressure of the raw milk in"'pass'a'ge 9 and branch l8. When, however, thispressure relation is reversed due to some abnormal condition, the microswitch 23 opens its contacts, thereby interrupting the operating circuit'of relay 43, which releases. The release of relay 43 opens the operating circuit of the motor p' mpjlZ, which immediately stops. The pressure 4 of the raw milk in passage 9 promptly drops to zero, so that there can be no leakage of raw milk into the pasteurized milk.

What I claim is:

1. In a, pasteurizing system, a heating unit provided with a primary passage for a heating liquid and with a secondary passage for a liquid to be heated, said passages being in heat exchange relation with each other, means for causing said heating liquid to flow through said primary passage at a given pressure, and means for causing the liquid to be heated to flow through said secondary passage at a pressure normally lower than said given pressure, and means responsive to a change in the normal pressure relation between the liquids in said passages for stopping the flow of liquid through said secondary passages.

2. In a pasteurizing system, a heating unit provided with a primary passage for a heating liquid and with a secondary passage for a liquid to be heated, said passages being in heat exchange relation with each other, means for causing said heating liquid to flow through said primary passage at a given pressure, means including a pump for causing the liquid to be heated to flow through said secondary passage at a pressure normally lower than said given pressure, and means responsive to a change in the normal'pressure relation between the liquids in said passages for stopping said pump.

3.- In a pasteurizing system, a heating unit provided with a primary passage for a heating liquid and with a secondary passage for a liquid to be heated, said passages being in heat exchange relation with each other, means for causing said heating liquid to flow through said primary passage at a given pressure, means including an electrically operated pump and a circuit therefor for causing the liquid to be heated to flow through said secondary passage at a pressure normally lower than said given pressure, and differential pressure means responsive to a change in the normal pressure relation between the liquids in said passages for stopping said pump, said differential pressure means including a diaphragm exposed to the pressure of the liquid in the primary passage, a second diaphragm exposed to the pressure ofthe liquid in the secondary passage, and a switch jointly actuated. by said diaphragms, said switch serving to control said circuit.

RAYMOND E. OLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,459,218 Knaak June 19, 1923 2,031,502 Powell Feb. 18, 1936 2,254,387 Olcott Sept. 2, 1941 

